The SDK platform-tools version ((21)) is too old to check APIs compiled with API 23

android studio是个坑爹的工具，每次打开文件头都出现如上错误提示。

解决方法：

Update your android sdk platform-tools to the revision 23.0.1 from sdk manager. In android studio click File->Invalidate Caches/Restart...

原文：http://www.cnblogs.com/antyi/p/5416362.html